For analysis of samples, for example body fluids such as blood or urine, test element analysis systems are often used in which the samples to be analyzed are applied to a test element and, if appropriate, react with one or more reagents in a test field on the test element before they are analyzed. Optical, in particular photometric, evaluation of test elements is one of the most common methods used for rapid determination of the concentration of analytes in samples. Photometric evaluations are generally used in the fields of analysis, environmental analysis and, above all, in medical diagnostics. Test elements that are evaluated photometrically have an important place, particularly in the field of blood glucose diagnosis from capillary blood.
Portable measurement appliances for blood sugar determination have become increasingly popular in recent years. They allow blood sugar measurement values to be determined at any desired time by means of an easy-to-use measurement appliance, a puncture aid, optimized in terms of the pain caused by the puncture, and a disposable test element, and in this way they permit more precise insulin doses for stabilizing the patient's blood sugar value. Most of the presently available blood sugar measurement appliances involve separate individual test elements, measurement appliances and puncture aids. The individual test elements are removed from a moisture-proof individual package by the patient. Blood is obtained by puncturing the skin with a puncture aid. A required minimum amount of blood is then applied to the test element, and a measurement is carried out using the measurement appliance.
There are different kinds of test elements. For example, substantially square slides are known in the middle of which a multilayer test field is located. Diagnostic test elements of strip shape are referred to as test strips. The prior art discloses capillary test elements for spatial separation of the detection zone and the sample application site of a test element.
WO 99/29429 relates to an analytical test element for determination of an analyte in a liquid, with an inert carrier, a detection element and a channel that permits capillary transport of liquid, and with a sample application opening at one end and an air outlet opening at the other end of the channel for the capillary transport of liquid. The channel permitting capillary transport of liquid is at least partially formed by the carrier and the detection element and extends, in the direction of capillary transport, from the sample application opening as far as the edge of the detection element lying closest to the air outlet opening.
The package holding the respective test element is designed to satisfy the main conditions for maintaining the function of the chemical and biochemical components on the test element during a long storage period. These conditions are, in particular, protection against the effects of light, protection against entry of moisture, dirt, microbes and dust, and protection against mechanical deterioration of the test elements.
As an alternative to individual packages, storage containers are known which contain a multiplicity of individually removable test elements and provide a sufficiently large amount of desiccant for absorbing the moisture introduced by opening and removal of a test element, thereby ensuring a sufficient storage period for all the test elements contained in the container. A storage container of this kind is known from EP 0 640 393 B1. In the storage container, the test elements are held as in a quiver, from which they can be removed when the storage system is opened.
Another suitable form of a storage container for test elements are aluminum or plastic tubes that are closed by a press-on or screw-on stopper. These storage containers have the disadvantage that the individual test elements have to be manually removed in an awkward way. A patient, for example one who wishes to perform a blood sugar test, has to carry around not just the measurement appliance, but also a puncture aid and a separate test element storage container. Besides this inconvenience, a particular disadvantage is that, when a test element is removed, this test element and/or another one is contaminated, and the contamination can lead to incorrect measurement results. There is a danger of test strips becoming contaminated by dirt adhering to the patient's hands or by the test element falling out.
Another known alternative is for a certain number of test elements to be stored in the measurement appliance itself.
DE 198 19 407 discloses a container for blood sugar measurement appliances or other measurement appliances operating with disposable test strips that can be fed to a sensor for measurement purposes, said container comprising two parts, in the first of which the test strips are stored, and in the second of which the used test strips are collected. The test elements can be arranged alongside one another so that they form a band, which can be wound rather like the tape in an audio cassette. Instead of this, they can also be arranged so as to form a round plate, on which they are placed at a defined distance from one another in the area of the plate circumference, so that, when the plate is rotated, a new test field comes into the corresponding measurement position. Another possibility is for the test strips to form a stack from which they are individually removed by a mechanism, and the test strips are brought one after another into the corresponding measurement position and, after the measurement, are brought into a collecting chamber.
EP 0 622 119 A1 discloses substantially rectangular magazines with mutually parallel chambers lying alongside one another in a line.
When the test elements are stored in the measurement appliance itself, the storage container, or the chamber in which a test element is located, is opened by an opening mechanism, and the test element is brought by a movement mechanism into a sample application position.
DE 198 54 316 A1 describes a storage container with separate moisture-proof chambers for test elements. Each of the chambers has at least two openings lying opposite one another and each closed by a sealing film. To remove the test elements, a test element is pushed out of its chamber with the aid of a ram. The ram cuts through the sealing film on one side of the chamber and then presses on the test element which, because of this pressure from the ram, cuts through the sealing film on the opposite side, so that the test element can be pushed out of the chamber. Other mechanisms for automatic removal of test elements from a storage container are disclosed in EP 0 738 666 B1 for a storage container in the form of a drum, in EP 0 662 626 B1 and EP 0 732 590 A2 for a storage container in the form of a disk, and in WO 02/08753 A2 for stacked storage of the test elements.
After a sample (for example blood) has been applied to the removed test element, detection and measurement data evaluation take place in the measurement appliance. After removal of the test element by the patient, or by another mechanism integrated in the appliance, the storage container is automatically positioned such that a further measurement can take place.
In the prior art, the test elements are normally protected, in particular against entry of moisture, by sealing the storage container or by sealing individual chambers of the storage container for the test elements. The sealing is provided, for example, in the form of a suitable film material with low water-vapor permeability (for example aluminum film coated with adhesive plastic). Moreover, the test elements are often protected against moisture by a desiccant being introduced into the storage container or into the chambers.
The devices known in the prior art, which integrate the provision of test elements, the sample application function and the measurement function within the measurement appliance, have the disadvantage that their construction is very complex. This complexity arises in particular from the fact that each test element has to be transported to different positions within the device (from the storage container to the sample application site, to the measurement position and then to the disposal site). Moreover, the test elements in the prior art have to be protected in an elaborate manner against moisture in particular. The filling and sealing of the storage container, integrated in the device and serving for storage of the test elements, is a cost-intensive and time-consuming procedure.
DE 100 57 832 C1 describes a blood analysis appliance with a simplified construction, which forms a complete system consisting of a puncture element, a blood collection device, test elements comprising a test field, and an evaluation means. The test elements are inserted into a magazine and, in order to carry out a number of measurements, can be brought one after another into a working position. When a respective test element is positioned in the working position, a puncture element can be pushed through the test element and inserted into the surface of a user's skin. The blood emerging from the surface of the skin impacts directly on the test element. This blood analysis appliance has the disadvantage that the test field itself is pierced, with the result that toxic components of the test field may remain adhering to the puncture aid and may be carried into the puncture wound in the user's skin.